Search results for " multiple"
showing 10 items of 903 documents
All-optical simultaneous polarization attraction and intensity regeneration of a 40-Gbit/s RZ signal
2011
We experimentally report the dual all-optical instantaneous regeneration of both the state of polarization and the intensity profile of a 40 Gbit/s Return-to-Zero telecommunication signal by means of a unique segment fiber.
Lossless equalization of frequency combs
2008
Frequency combs obtained by sinusoidal phase modulation of narrow-band continuous-wave lasers are widely used in the field of optical communications. However, the resulting spectral envelope of the comb is not at. In this Letter, we propose a general and eficient approach to achieve at frequency combs with tunable bandwidth. The idea is based on a two-step process. First, eficient generation of a train with temporal at-top-pulse profile is required. Second, we use large parabolic phase modulation in every train period in order to map the temporal intensity shape into the spectral domain. In this way, the resulting spectral envelope is at and the size is tunable with the chirping rate. Two d…
CSRZ-ASK and DPSK 40 Gb/s All-Raman WDM Transmission Based on UltraWave Fiber
2006
In this paper, we report a complete experimental and numerical analysis of 40 Gb/s WDM ultra long-haul (ULH) transmission using CSRZ-DPSK and CSRZ-ASK modulation formats on UltraWavetrade fiber spans. Experimental results compare well with full numerical simulations
Kerr frequency comb generation in the normal dispersion regime of dispersion oscillating telecom fiber
2013
The generation of optical frequency combs has a variety of applications from optical metrology to spectroscopy and wavelength division multiplexing. Nonlinear methods to generate frequency combs are based on multiple four-wave mixing (FWM) in highly nonlinear waveguides [1]. The mechanism for the generation of a wideband comb from a CW pump is Kerr-induced phase-matching of the FWM interaction or modulation instability (MI), which requires operating in the anomalous dispersion regime. Such restriction can be circumvented with a cavity geometry, where MI [2] and comb generation [3] may also be observed in the normal dispersion region. Alternatively, one may obtain MI and unequally spaced Ker…
Wavelength-flattened directional couplers for mirror-symmetric interferometers
2005
In the context of guided optics, we derive, analytically and geometrically, a rigorous general criterion to design wavelength insensitive interferometers with mirror symmetry, which are needed for wavelength multiplexing/demultiplexing. The criterion is applied to a practical case, resulting in an interferometer that works on a band wider than 70 nm.
Tunable arrayed waveguide grating driven by surface acoustic waves
2016
We present a design approach for compact reconfigurable phased-array wavelength-division multiplexing (WDM) devices with N access waveguides (WGs) based on multimode interference (MMI) couplers. The proposed devices comprise two MMI couplers which are employed as power splitters and combiners, respectively, linked by an array of N single-mode WGs. First, passive devices are explored. Taking advantage of the transfer phases between the access ports of the MMI couplers, we derive very simple phase relations between the arms that provide wavelength dispersion at the output plane of the devices. When the effective refractive index of the WGs is modulated with the proper relative optical phase d…
Resolution improvement by single-exposure superresolved interferometric microscopy with a monochrome sensor
2011
Single-exposure superresolved interferometric microscopy (SESRIM) by RGB multiplexing has recently been proposed as a way to achieve one-dimensional superresolved imaging in digital holographic microscopy by a single-color CCD snapshot [Opt. Lett. 36, 885 (2011)]. Here we provide the mathematical basis for the operating principle of SESRIM, while we also present a different experimental configuration where the color CCD camera is replaced by a monochrome (B&W) CCD camera. To maintain the single-exposure working principle, the object field of view (FOV) is restricted and the holographic recording is based on image-plane wavelength-dispersion spatial multiplexing to separately record the thre…
Design scheme for Mach–Zehnder interferometric coarse wavelength division multiplexing splitters and combiners
2006
I propose an analytical approach to design flattened wavelength splitters with cascaded Mach–Zehnder inter- ferometers when wavelength dependence of the directional couplers cannot be neglected. I start from a geo- metrical representation of the action of a doubly point-symmetrical filter, assuming no wavelength dependence of the couplers. Next I derive the analytical formulas behind its working principle and extend them to the wavelength-dependent case. I also show how the geometrical representation allows one to broaden the class of working structures. © 2006 Optical Society of America
High performance configuration of all-raman N &#x000D7; 40 Gbit/s RZ-DPSK systems over ultrawave<sup>TM</sup> maps
2007
In order to explore the impact of the DPSK format on best system configuration, and to cross-check the simulation tools, transmission experiments involving 16 × 40 Gbit/s WDM channels on a recirculating loop including a symmetric UltrawaveTM fiber dispersion map are performed. In these experiments the RZ-DPSK format is used, and each 100 km span is brought to optical transparency with 75%(25%) of backward (forward) Raman gain. The pre-compensation is experimentally varied, and a significant transmission improvement after 4000 km for the pre-compensation of -350 ps/nm is observed.
Instabilities of four-wave mixing
2005
We predict that four-wave mixing driven by a dual frequency input undergoes different instability scenarios encompassing modulational instability or multiple shock formation in the anomalous and normal dispersion regime, respectively.